1. Field of the Invention
The present invention relates to spring biased vehicle closure hinges having a laterally coiled spring in integral construction with a link assembly having a reduced footprint for improved packaging in restricted areas, for example, the peripheral channel adjacent to a vehicle opening such as a rear trunk compartment.
2. Background Art
Many previously known vehicle closure hinges such as those used for engine compartment hoods and trunk lids often include spring biasing to assist displacement of the heavy panel which is displaced about a pivot axis at one end of the panel. However, a spring biasing assist force sufficient to maintain the closure in a fully open position is often provided by additional structure such as a prop rod, gas struts or the like to resist closure of the closure panel by the weight of the panel acting in a moment arm about the pivot axis or force transfer through a linkage.
One method to increase the spring biasing has been to use the torsion rods that can be routed across the car. However, while such spring biasing can be strong enough to resist closure, since the entire length of the torsion rod provides spring biasing force, the elongated torsion rods can obstruct and form a substantial impediment to the access through the opening or within the compartment covered by the closure panel. Other improvements to spring design, such as gas powered struts or powerful springs often require multiple installation steps since the spring biasing force unit must be separately installed to assist a conventional hinge structure. Such improvements substantially increase the difficulty of production, rendering the use of such components prohibitively expensive because they add production steps as well as additional pieces and mass to the vehicle. In the case of a gas strut power source, in a closed position the line up force in the strut is directed to the hinge pivot, thus forcing the pivot to endure high loading that shortens useful life of the original installation. Also, the life of a gas strut is both time-dependent and cycle-dependent, making it much less durable than a steel spring.
Moreover, once the spring force has been determined for a particular application, the hinge designs may not be readily incorporated into other vehicles having differently sized, weighted or balanced mass or center of gravity than the installation for which it was designed. As a result, the alternative assemblies may need redesigned linkage and/or biasing structures for each particular closure panel type, thereby substantially multiplying the number of assemblies and production pieces that must be made and inventoried in order to accommodate production and repair of the vehicles despite similar hinge needs and arrangements in the various openings of different vehicle styles.
A previously known attempt to address the problems discussed above involves the use of a single pivot arm as part of a four bar link assembly and integral clock spring. However, while the clock spring may provide substantial flexibility in the design and spring biasing force applied to a hinge mechanism, such springs require an extremely large envelope vertically as well as fore-and-aft to accommodate the four bar linkage and the coil spring. Moreover, the previous designs of this type have been complex requiring numerous parts and assembly operations, the addition of parts rendering the hinge relatively heavy, and thus have not found favor in many production applications due to the large expense compared to more conventional systems.